In SoMI the Monkey Island part is boring, with the exception of the section on LeChuck's ship. In this particular case, the puzzles are not bad per se, but they're not good either. They're just there, failing to captivate. And the island itself is boring. I guess you could say that it's subjective, and I agree, but Monkey Island is usually people's least favourite part when it comes to SoMI, judging by my conversations with different people.
I do consider ending of CMI to be on Monkey Island (since, well... it IS on Monkey Island), and the fake pie puzzle and what else was there never made sense to me. And I consider the roller-coaster's existence to be almost as ridiculous as giant robot's existence. (And, to all who says that EMI is not piratey, since when roller-coasters are piratey? Heck, Murray's joke regarding the Carnival's destruction in EMI was one of my favourites because the Carnival itself is so damn out of place

)
I do agree that EMI could be called the worst offender when it comes to the Monkey Island section on the game, but I just think that Monkey Island has always been problematic and that it shouldn't be included at all in any other Monkey Island game. Ever. Really, the games are better off without it. For me that's the Curse of Monkey Island. Games are absolutely awesome right until the point where you get to Monkey Island itself, and then things go haywire. And, funnily enough, Monkey Island 2 and Tales don't have Monkey Island in the end (Dinky may be retconned to be close to Monkey, it's still NOT Monkey

), and they don't have that problem.
EDIT: And, just so you know, even when I try to be objective as possible, it's still all my personal opinion.
EDIT2: I loved Charity James, honestly. If they ever try to make SE of EMI, however unlikely that is, if they replace Charity James with Alexandra Boyd, I'm gonna kill them. Don't really have anything against Alexandra Boyd, but don't touch Charity!